Gas turbine engines, such as those which power aircraft and industrial equipment, employ a compressor to compress air that is drawn into the engine and a turbine to capture energy associated with the combustion of a fuel-air mixture. Seals are used in engines to isolate a fluid from one or more areas/regions of the engine. For example, seals control various parameters (e.g., temperature, pressure) within the areas/regions of the engine and ensure proper/efficient engine operation and stability.
Referring to FIG. 2A, a prior art sealing system 200 of an engine is shown. The system 200 is shown as including a bearing ring 206, a distribution feature 212, a seal plate 218, a carbon segment 224, and a carrier 230. The bearing ring 206 may be part of a larger bearing system/compartment that may support rotational hardware of the engine. The carrier 230 may support the carbon segment 224.
The seal plate 218 is configured to rotate, whereas the carbon segment 224 is a stationary structure. In this respect, an interface 236 between the seal plate 218 and the carbon segment 224 may be subject to heat/thermal loads that need to be managed. Opposed to, and axially forward of the interface 236 is a planar end face 252 of the seal plate 218. The distribution feature 212 is used to convey oil to the seal plate 218 to cool the seal plate 218 in support of such thermal management. The seal plate 218 includes radially-oriented holes 258 (see FIG. 2B) that cool the seal plate 218 at discrete locations around the circumference of the seal plate 218. The oil is ejected radially outward/outboard from the seal plate 218 via the holes 258.
The holes 258 have a relatively small surface area for the cool oil to draw heat away from the seal plate 218. The oil passes through the holes 258 quickly, with minimal time for the oil to cool the seal plate 218. Moreover, the use of the holes 258 provides for cooling at discrete locations on the seal plate 218. For example, and as best seen in FIG. 2B, those portions 218a of the seal plate 218 that are proximate to the holes 258 may tend to be cooler than those portions 218b of the seal plate 218 that are further from the holes 258, such that the seal plate 218 may be subject to waviness/lack of uniformity due to variations in a distance of locations/portions of the seal plate 218 relative to the holes 258.
Bearing compartment heat generation, which is influenced by oil flow rate, necessitates the use of fuel/oil and air/oil heat exchangers. For example, in order to cool the hardware as described above, relatively large oil flow rates may be needed in order to continue circulating cool oil to, e.g., the seal plate 218. The oil flow rates that are used dictate the sizes of an oil pump, tubes, and an oil tank. For example, the use of a large oil flow rate may result in the use of large oil pumps, tubes, and oil tanks. An increase in the size of the oil pumps, tubes, and oil tanks increases the weight of the engine, which has a negative impact on engine efficiency/performance.